Layered transition metal dichalcogenide (TMD) nanomaterials are promising alternatives to platinum (Pt) for the hydrogen evolution reaction (HER). However, the family of layered TMDs is mainly limited to Group IV-VII transition metals, while the synthesis of layered TMDs based on metals from other groups still remains a challenge. Herein, we demonstrate by atomic-resolution transmission electron microscopy that hexagonal RuSe 2 (h-RuSe 2) nanosheets with a mixture of 2H and 1T phases can be obtained by a facile bottom-up colloidal synthetic approach. The obtained h-RuSe 2 , which can be transformed into the thermodynamically favorable phase of cubic RuSe 2 (c-RuSe 2) only after annealing at 600 8C, exhibits Pt-like HER performance, with a fivefold turnover frequency enhancement compared to the c-RuSe 2 in alkaline media. Experimental results and density functional theory (DFT) calculations reveal that the enhanced adsorption free energies of H 2 O (DG H 2 O *), optimized adsorption free energies of H (DG H*), and increased conductivity of h-RuSe 2 contribute to its superior HER activity.
Exploring efficient electrocatalysts applied for the hydrogen oxidation reaction (HOR) and the hydrogen evolution reaction (HER) under alkaline electrolytes and fundamentally understanding the corresponding reaction mechanisms are crucial to realizing the reversible conversion of hydrogen energy. Much work has been devoted to boosting alkaline HOR/HER performances by promoting the hydroxide binding energy (OHBE) but little on understanding the correlation between them. Herein, the synthesis of Momodified Ru catalysts with an almost identical hydrogen binding energy (HBE) is reported, and the structure−activity correlation during the HOR/HER is studied. By combining experimental data and theoretical calculations, a volcanotype relationship of HOR/HER performance with OHBE values is provided. Density functional theory (DFT) further reveals that the optimal OHBE, together with the decreased reaction energy barrier for water formation/ dissociation, contributes to remarkable alkaline HOR/HER performance.
High-entropy alloy (HEA) catalysts have been widely studied in electrocatalysis. However, identifying atomic structure of HEA with complex atomic arrangement is challenging, which seriously hinders the fundamental understanding of catalytic mechanism. Here, we report a HEA-PdNiRuIrRh catalyst with remarkable mass activity of 3.25 mA μg À 1 for alkaline hydrogen oxidation reaction (HOR), which is 8-fold enhancement compared to that of commercial Pt/C. Through machine learning potential-based Monte Carlo simulation, we reveal that the dominant PdÀ PdÀ Ni/PdÀ PdÀ Pd bonding environments and Ni/Ru oxophilic sites on HEA surface are beneficial to the optimized adsorption/desorption of *H and enhanced *OH adsorption, contributing to the excellent HOR activity and stability. This work provides significant insights into atomic structure and catalytic mechanism for HEA and offers novel prospects for developing advanced HOR electrocatalysts.
Layered transition metal dichalcogenide (TMD) nanomaterials are promising alternatives to platinum (Pt) for the hydrogen evolution reaction (HER). However, the family of layered TMDs is mainly limited to Group IV–VII transition metals, while the synthesis of layered TMDs based on metals from other groups still remains a challenge. Herein, we demonstrate by atomic‐resolution transmission electron microscopy that hexagonal RuSe2 (h‐RuSe2) nanosheets with a mixture of 2H and 1T phases can be obtained by a facile bottom‐up colloidal synthetic approach. The obtained h‐RuSe2, which can be transformed into the thermodynamically favorable phase of cubic RuSe2 (c‐RuSe2) only after annealing at 600 °C, exhibits Pt‐like HER performance, with a fivefold turnover frequency enhancement compared to the c‐RuSe2 in alkaline media. Experimental results and density functional theory (DFT) calculations reveal that the enhanced adsorption free energies of H2O (ΔGnormalH2normalO*
), optimized adsorption free energies of H (ΔGH*), and increased conductivity of h‐RuSe2 contribute to its superior HER activity.
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